Looking at the probably fair system, I have one doubt, what prevents you from generating an exact txid to win the prize when many people bets? Because you can actually see the salt (it is in your server). Provably fair means that a casino can't take the win from the player or modify it, but here you can find a txid that merged with the salt gives you the victory. I don't know how could you find a way to fix this...
Thank you for reviewing our provably fair algorithm. Yes, our goal is to have a system that not even the house can exploit.
The txid that we are using is txid from bitcoin blockchain itself. We even link directly to blockchain.info so it is not up to us to generate txid. In fact it is generated at players' wallets.
Salt for each tournaments are predetermined even before we get our first entries. While our gut feeling tells that we can publish salt even before tournament concludes, just to be extra safe, we decides to instead publish sha256 hash of salt from start of tournament. When tournament concludes, actual salt will be revealed and that can be validated with the sha256 hash that has been published.
As far as I can tell, I do not think we are able to exploit it even knowing the salt.
Or perhaps, we should make it fair and just publish the salt right away as I don't think it is exploitable, right?
Thanks once again for reviewing it. We would like to create a safe and trustworthy tournament environment for all. Eventually our goal is to allow even 3rd parties to organize tournaments on our platform.